The use of global distribution systems such as the Internet for distribution of digital assets such as music, film, computer programs, pictures, games and other content continues to grow. In many instances, media offered via traditional broadcast mediums is supplemented through similar media offerings through computer networks and the Internet. It is estimated that Internet-related media offerings will rival and even surpass traditional broadcast offerings in the coming years.
Techniques such as “watermarking” have been known in the art for incorporating information signals into media signals or executable code. Typical watermarks may include encoded indications of authorship, content, lineage, existence of copyright, or the like. Alternatively, other information may be incorporated into audio signals, either concerning the signal itself, or unrelated to it. The information may be incorporated in an audio signal for various purposes, such as identification or as an address or command, whether or not related to the signal itself.
There is considerable interest in encoding audio signals with information to produce encoded audio signals having substantially the same perceptible characteristics as the original unencoded audio signals. Recent successful techniques exploit the psychoacoustic masking effect of the human auditory system whereby certain sounds are humanly imperceptible when received along with other sounds.
Arbitron has developed a new and innovative technology called Critical Band Encoding Technology (CBET) that encompasses all forms of audio and video broadcasts in the measurement of audience participation. This technology dramatically increases the both the accuracy of the measurement and the quantity of useable and effective data across all types of signal broadcasts. CBET is an encoding technique that Arbitron developed and that embeds identifying information (ID code) or other information within the audio portion of a broadcast. An audio signal is broadcast within the actual audio signal of the program, in a manner that makes the ID code inaudible, to all locations the program is broadcast, for example, a car radio, home stereo, computer network, television, etc. This embedded audio signal or ID code is then picked up by small (pager-size) specially designed receiving stations called Portable People Meters (PPM), which capture the encoded identifying signal, and store the information along with a time stamp in memory for retrieval at a later time. A microphone contained within the PPM receives the audio signal, which contains within it the ID code.
Further disclosures related to CBET encoding may be found in U.S. Pat. No. 5,450,490 and U.S. Pat. No. 5,764,763 (Jensen et al.) in which information is represented by a multiple-frequency code signal which is incorporated into an audio signal based upon the masking ability of the audio signal. Additional examples include U.S. Pat. No. 6,871,180 (Neuhauser et al.) and U.S. Pat. No. 6,845,360 (Jensen et al.), where numerous messages represented by multiple frequency code signals are incorporated to produce and encoded audio signal. Other examples include U.S. Pat. No. 7,239,981 (Kolessar et al.). Each of the above-mentioned patents is incorporated by reference in its entirety herein.
The encoded audio signal described above is suitable for broadcast transmission and reception and may be adapted for Internet transmission, reception, recording and reproduction. When received, the audio signal is processed to detect the presence of the multiple-frequency code signal. Sometimes, only a portion of the multiple-frequency code signal, e.g., a number of single frequency code components, inserted into the original audio signal, is detected in the received audio signal. However, if a sufficient quantity of code components is detected, the information signal itself may be recovered.
Other means of watermarking have been used in various forms to track multimedia over computer networks and to detect if a user is authorized to access and play the multimedia. For certain digital media, metadata is transmitted along with media signals. This metadata can be used to carry one or more identifiers that are mapped to metadata or actions. The metadata can be encoded at the time of broadcast or prior to broadcasting. Decoding of the identifier may be performed at a digital receiver. Other means of watermarking include the combination of digital watermarking with various encryption techniques known in the art.
While various encoding and watermarking techniques have been used to track and protect digital data, there have been insufficient advances in the fields of cross-platform digital media monitoring. Specifically, in cases where a person's exposure to Internet digital media is monitored in addition to exposure to other forms of digital media (e.g., radio, television, etc.), conventional watermarking systems have shown themselves unable to effectively monitor and track media exposure. Furthermore, there is a need to integrate exposure to digital media across platforms where the digital media includes formats that are not traditionally subject to audio encoding. Moreover, there is a need in the art to properly “mask” such signals using environmental sounds and/or sounds native to a device that is conducting beaconing processes.